An extension or addition to your house is considered to be permitted development, not requiring
an application for planning permission, provided certain limits and conditions are met.
1. On designated land cladding of any part of the exterior of a dwelling (and extensions) with stone, artificial stone, pebble dash, render, timber, plastic or tiles is not permitted development.
* Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.
2. Extensions (including previous extensions) and other buildings must not exceed 50% of the total area of land around the original house. The term ‘original house’ means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so.
* Sheds and other outbuildings must be included when calculating the above 50% limit.
3. Extensions forward of the principal elevation or side elevation of a house and fronting a highway are NOT permitted development.
4. On designated land side extensions are not permitted development.
5. Materials used in exterior work to be similar in appearance to those of the exterior of the existing house. This condition does not apply when the extension is a conservatory.
6. Width of side extension must not have a width greater than half the width of the original house.
7. Side extensions to be single storey with a maximum height of four metres.
8. If extension is within two metres of a boundary maximum eaves height should be no higher than three metres to be permitted development.
9. Single-storey rear extension must not extend beyond the rear of the original house by more than three metres if an attached house or by four metres if a detached house.
10. Single storey rear extension must not exceed a height of four metres.
11. Maximum eaves and ridge height of extension no higher than existing house.
Crown Copyright©2011 Reproduced with permission